Method and device for the sequential supply of articles to be processed

ABSTRACT

For allowing a reduction in the processing capacity to be accommodated without delay in a system, in which articles are supplied and transferred to an article processing device ( 8 ) from an article delivering device ( 4 ) in a regularly clock cycled supply stream, articles are not transferred to the article processing device when there is no processing capacity. Instead they are conveyed onwards along a return track ( 9 ) and are re-introduced into the supply stream at a return point ( 6 ) upstream of the transfer point ( 7 ). For each re-introduction of a returned article into the supply stream, a gap is produced in the supply stream in a gap formation point ( 5 ) upstream of the return point ( 6 ). For synchronizing returned articles and gaps, the length (in clock cycles) of the return track ( 9 ) is matched to the length (in clock cycles) of the supply track ( 3 ) from the gap formation point ( 5 ) to the return point ( 6 ) and to a time difference (in clock cycles) between a non-transfer and formation of a corresponding gap. The system is suitable in particular for supplying main products from a web-fed printing press to a stacking/packaging device where normal packages and peak packages are produced. The main products are completed prior to be stacked and packed. In this application it is possible to operate the article supply regularly clock cycled although no separate processing device for producing the peak packages is provided and although no completed products are to be removed from the system.

FIELD OF THE INVENTION

[0001] The invention is related to the field of piece goods processingand concerns a method and a device for the sequential supply of a largenumber of articles to a processing operation, i.e. for conveying thearticles to a processing device and for transferring the articles forbeing processed.

BACKGROUND OF THE INVENTION

[0002] Sequential supply of articles to a processing operation is simpleboth with respect to the device as well as with respect to control,providing that processing can be operated regularly clocked throughout.Supply and processing are in such a case advantageously fixedly coupledthrough a common drive or through a common control system in such amanner that variations in the processing capacity (number of articlesprocessed per unit of time) are taken up by the supply system withoutdelay. Fixedly coupled systems of this kind can only be used, if thearticles to be supplied to processing are retrieved from a reservoir(e.g., off-line supply from storage formations) and if retrieval fromthe reservoir can be adapted to fluctuations in the processingperformance without delay.

[0003] For on-line supply, i.e., for supplying articles which are e.g.delivered directly from a manufacturing device, systems with fixedlycoupled supply and processing are not advantageous, if performancevariations of the processing operation are to be expected and if it isnot possible or possible only with a temporal delay to adapt thedelivering capacity to a momentary processing capacity.

[0004] For avoiding the disadvantages of systems in which, as brieflydescribed above, supply and processing are coupled by a system clocking,the supply means may comprise a switch-point for removing suppliedarticles from the system, when there is no processing capacity availablefor them. For enabling the system to react to unforeseen reductions ofthe processing capacity, the articles are removed from the systemimmediately before being processed. Supply systems comprising articleremoval means can be operated in a regularly clocked manner even if theprocessing capacity is not constant and therefore, they can beimplemented in a relatively simple manner even for held conveyance, e.g.using circulating gripper chains having regularly spaced grippers andbeing driven with a substantially constant speed. If, however, theprocessing capacity lies below the supply capacity to a considerabledegree or for a longer time period, then a large number of removedarticles accumulates. These articles either have to be rejected or elseare to be re-supplied into the system at a suitable point and at asuitable time, usually by manual labour.

[0005] Removal of supplied articles from the system for compensating areduction in processing capacity is prevented according to prior art,e.g. by installing a further processing device for processing articleswhich cannot be processed by the first processing device. This furtherdevice, however, represents a great additional expense and theutilisation factor of this device in many instances is very low.

[0006] More elegant, however, with respect to the devices even moreelaborate, are solutions to the same problem in which the supply is notoperated in a strictly clocked manner, but comprises a buffer stretchde-coupling the article delivery (e.g., on-line from production oroff-line from a store) and the article transfer to the processingoperation. Such systems are capable to combine within limits given bythe buffer capacity, a constant delivery performance with fluctuationsin the processing capacity or with delays in adapting the deliveryperformance to a varying processing capacity. Buffer stretches, however,call for conveyance with varying distances between the articles,which—while able to be implemented in a relatively simple manner forconveyance of loosely lying articles—necessitates elaborate systems forgripped conveyance, i.e. holding elements capable of being conveyedindependently of one another.

[0007] An example for illustrating the problems and difficultiesdescribed in brief above in a simple manner is the stacking andpackaging (processing) of printed products, which, for example, areproduced in a web-fed printing machine and which between the web-fedprinting machine and the stacking/packaging are completed on-line byaddition of partial products, of supplements and/or of other products.Stacking and packaging can only be carried out in a regularly clockedmanner, if all packages to be produced are of the same size. If,however, for individual destinations predetermined numbers of printedproducts are to be packed in groups of maximum sized standard packagesand smaller peak packages, then the stacking/packaging capacity (inprinted products per unit of time) is smaller during production of peakpackages than during production of standard packages. Because in thiscase adaptation of the delivery speed of the web-fed printing press tovariations in the stacking/packing capacity does not make any sense,usually an additional device is provided for producing the peak packagesand the printed products to be packed in peak packages are supplied tothis additional device by being conveyed past the stacking device forstandard packages. Because commercially available stacking/packagingdevices are usually able to produce both standard packages as well aspeak packages without problem and because the peak packages only accountfor a small proportion of the overall volume, it would be desirable tobe able to do without the additional, not very well utilised device forthe production of the peak packages. This would be even more desirable,if possible without calling for a buffer stretch before stacking,without increased complexity of the whole installation and in particularwithout removal of completed printed products before stacking, whichremoved completed products need to be disassembled for re-introductioninto the system.

BRIEF DESCRIPTION OF THE INVENTION

[0008] In particular in order to fulfil the above desire of the printingsector, the invention sets itself the objective of creating a method anda device for sequential supply of articles (e.g., printed products)delivered e.g. on-line (e.g., from a web-fed printing press) to aprocessing operation (e.g., stacking and packaging). Method and deviceaccording to the invention are to make it possible to, in a most simplemanner, to absorb temporary reductions of the processing capacitywithout influencing the supply capacity and without the necessity of abuffer stretch or of an additional processing device. The deviceaccording to the invention is to be simple. In particular it is to beable to be implemented using simple conveying means which can only beoperated in a rigid clock cycling regime.

[0009] The method and the device according to the invention are to beparticularly advantageously useable for the above example of theproduction of printed products including on-line completion andstacking/packaging in standard and peak packages. However, use of methodand device according to the invention shall in no way be restricted tothis example.

[0010] The method in accordance with the invention is based on the ideaof removing articles from a regularly clocked supply stream in order toadapt the supply performance to a temporarily reduced processingcapacity. However, whereas according to prior art the removal takesplace immediately on transfer of the articles to the processingoperation, according to the invention, removal is displaced to a freelyselectable point further upstream, advantageously upstream of a furtherprocessing device for on-line processing of the articles before transferto the final processing operation (e.g., on-line completion).

[0011] This is achieved by returning articles, which for lack ofprocessing capacity cannot be transferred to be processed and byre-introducing them into the supply stream in a location upstream of thetransfer point. In order to make re-introduction into the fixedlyclocked supply stream possible, corresponding gaps are established inthis stream in a controlled manner, such that there is a gap at thepoint of re-introduction (return point) whenever a returned article isto be re-introduced.

[0012] The supply track along which the articles are conveyed from adelivery device to the processing device comprises a gap formationpoint, a return point and a transfer point at the end of the track fromwhere the articles are transferred to the processing operation or fromwhere, if so required, they are returned to the return point along areturn track. The gap formation point is situated at the return point orupstream of the return point. The position of the gap formation pointcan be selected on the basis of any criteria. The length of the returntrack in conveying clock cycles is dependent on the geographicaldistance between the gap formation point and the return point as well ason the time difference (also in clock cycles) between a non-transfer anda corresponding gap formation. In this, a conveying clock cycle is to beunderstood as a locational unit, namely as the distance between twoarticles conveyed one behind the other, and as a temporal unit being,during operation, fixedly correlated with the locational unit throughthe conveying speed.

[0013] In a system, in which the articles in the supply stream stem froman on-line source, it is advantageous to form the gaps in the supplystream by removing articles from this stream. If, however, the articlesfor the supply stream are retrieved from a store it is possible also toform the gaps already on establishing the supply stream at the storeoutlet.

[0014] A device for carrying out the method according to the inventionbeing equipped for conveying the articles individually gripped can beimplemented with no other conveying devices than ones, which can beoperated in a regularly clocked manner only (advantageously circulatinggripper chains). For conveyance between the return point and thetransfer point along the supply track and along the return track, it isadvantageous to use one single circulating conveying means on whichholding means (e.g., grippers) are arranged at regular distances betweenone another. The holding means are controlled for gripping one articleeach, for conveying the article in a held manner and for releasing thearticle.

[0015] Along the supply track the articles may be subjected to furtheron-line processing steps both upstream of the return point as well asdownstream of it. Advantageously the gap formation point is positionedupstream of any such processing step and the further processing stepsare controlled for being able to deal with gaps and/or returned articlesin the supply stream. In this manner, only unprocessed articles areremoved from the supply stream for forming the gaps, i.e. articles whichcan be reintroduced into the system without problems. Furthermore,equipment which may be provided for other reasons anyway, can be usedfor the removal. Supply of articles according to the invention can beimplemented with the same, very simple conveying means as used for knownarticle supply methods in which articles not being able to betransferred to processing for lack of processing capacity are removedfrom the system. The principle advantage of the method according to theinvention, in comparison with such known supply methods, resides in thefact, that article removal (gap formation point) can be located at asubstantially freely selectable point of the supply track,advantageously at a point, at which easily recyclable (for example, notyet processed) articles are removed, or at a point, at which removalmeans are provided for other reasons. Despite the fact that removal (gapformation) may take place at a great distance from the processingoperation to which the articles are supplied, the system can react toprocessing capacity reductions essentially without any time delay.

[0016] In case of the above mentioned example for an application of theinvention, i.e. for stacking and packing of products immediately beforeon-line completed by addition of further products, the gaps in thesupply stream are formed upstream of the completion device. Completionis suspended for gaps. Articles which are not transferred to be stackedand packaged are re-introduced into the supply stream between thecompletion device and the transfer to stacking/packaging. This meansthat all completed products are processed by one and the samestacking/packaging device and the products removed from the system arenot completed (contain no further products) and can therefore berecycled into the system at a suitable time without further effort.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

[0017] Method and device in accordance with the invention and theexample of an application already sketched out further above (web-fedprinting press, on-line completion and packaging for producing printedproducts) are described in more detail on the basis of the followingfigures, wherein:

[0018]FIGS. 1 and 2 show two simple schematic process diagrams forexplaining the method according to the invention;

[0019]FIG. 3 shows a schematic horizontal projection layout of the namedapplication example;

[0020]FIGS. 4, 5 and 6 show three cross sections through the schematicdiagram of FIG. 3 with somewhat more detail (intersection lines IV-IV,V-V and VI-VI).

DETAILED DESCRIPTION OF THE INVENTION

[0021]FIGS. 1 and 2 show in a very schematic manner the method forsequential supply of articles 1 (depicted as crosses) to a processingoperation according to the invention. For the supply, the articles 1 areconveyed regularly clocked and held gripped along a supply track. Suchregularly clocked conveyance is illustrated in FIGS. 1 and 2 as a row ofcircles, wherein conveyed articles 1 are depicted as circles filled witha cross (on-line processed articles 1′ with an additional small circle)and gaps 2 as empty circles. Every circle represents a conveying clockcycle.

[0022] The supply track 3 leads from an article delivering device 4,from which articles are fed into the supply stream, past the gapformation point 5, where gaps are formed in the supply stream, to thereturn point 6, where articles 1 (possibly on-line processed articles1′) not transferred to processing are re-introduced into the supplystream, and from there to the transfer point 7, where possibly on-lineprocessed articles 1′ are transferred to the processing operation 8 orare returned. From the transfer point 7, the return track 9, on whichnot transferred, possibly on-line processed articles 1′ are returned,leads back to the return point 6. Upstream of the transfer point 7 or atthe transfer point 7 means can be provided for removing faulty productsfrom the supply stream (not illustrated).

[0023] In the case of a delivering device 4 operating on-line, the gapformation point is located downstream of the delivering device and thegaps 2 are formed by removing articles 1 from the supply stream. In thecase of a delivering device 4′ operating as store outlet it isadvantageous to locate the gap forming point 5 immediately at the storeoutlet, i.e., to correspondingly control retrieval of articles from thestore.

[0024] For synchronization of gaps 2 arriving at the return point 6along the supply track 3 and of not transferred and returned articles 1arriving at the return point 6 along the return track 9 such that theymeet in an controlled manner, the length (in conveying clock cycles) ofthe supply track 3 between the gap formation point 5 and the returnpoint 6, the length (in conveying clock cycles) of the return track 9and the time difference (in conveying clock cycles) between thenon-transfer of an article 1 and the formation of a corresponding gap 2in the supply stream have to be correspondingly matched. This matchingcan be adapted to various external conditions in various ways, as isillustrated in FIGS. 1 and 2.

[0025]FIG. 1 depicts a system, in which the articles 1 are to beprocessed on-line (e.g., completed) in a further processing device 10between the article delivering device 4 or 4′ and the return point 6 andin which no (on-line) processed articles are to be removed from thesupply stream. For this reason, the gap formation point 5 is arrangedupstream of the further processing device 10. The return track 9 and thesupply track 3 from the return point 6 to the transfer point 7 areadvantageously served by a single, circulating conveying organ, towhich, at the return point 6, the articles 1′ of the supply stream aretransferred from an other conveying organ.

[0026] The length of the supply track 3 between the gap formation point5 and the return point 6 is given mainly by the further processingdevice 10. If a gap is formed without any delay relative to anon-transfer of an article at the transfer point 7, the return path 9has the same length as the part of the supply track from the gapformation point 5 to the return point 6. A delay between non-transferand gap formation calls for a corresponding extension of the returntrack 9. If the non-transfer is decided on prior to the arrival of therespective article at the transfer point 7, gap formation can beinitialised early (negative delay) and the return track 9 can becorrespondingly shorter.

[0027] The further processing device 10 is to be controlled in such amanner, that processing steps are suspended for gaps 2 in the feeding-instream. In addition to a further processing device 10 located betweenthe gap formation point 5 and the return point 6, it is also possible toprovide another further processing device 11 between the return point 6and the transfer point 7. This device has to be controlled in such away, that processing is suspended for returned articles.

[0028]FIG. 2 illustrates a system, which comprises a further processingdevice 11 only between the return point 6 and the transfer point 7. Forthis reason, the length of the supply track 3 between the gap formationpoint and the transfer point 7 can be shortened in a freely selectablemanner. It can even have a zero length, as illustrated, such that thegap formation point 5 and the return point 6 coincide and an article isremoved simultaneously with the arrival of a returned article on thereturn track 9 at this point 5/6. The same as in the system according toFIG. 1, it is advantageous to realize the supply track 3 between thepoint 5/6 and the transfer point 7 and the return track 9 with a single,circulating conveying organ. For the supply track 3 upstream of thepoint 5/6, a further conveying organ is provided, which transfers thesupply stream at the point 5/6 and which conveys removed articlesonwards.

[0029]FIG. 3 is a plan view and illustrates an installation, in whichmain products of printed products (e.g., newspapers) are deliveredon-line by a web-fed printing press (article delivering device 4),on-line completed in a completion device 12 (further processing device10), e.g. an insertion drum, and from there are supplied to a stackingand packaging operation (article processing device 8). A further on-lineprocessing device between return point 6 and transfer point 7 (11 inFIG. 1) is not provided. Three part supply systems 13.1 to 13.3 areprovided for supplying part products (or supplements or other articles,etc.) from sheet feeders 14.1 to 14.3 and/or winding stations 15.1 to15.3 to the completion device 10. The installation in its essentialfeatures corresponds to the schematic diagram of FIG. 1. The samefunctional units are therefore designated with the same referencenumbers as in FIG. 1. The supply track 3, depicted in FIG. 3 as a boldline leads from the article delivering device 4 to the on-linecompletion device 12, e.g. in a spiral track through the completiondevice 12 and past the part supply points 16.1 to 16.3 and from thecompletion device 12 to the article processing device 8. The gapformation point 5 is situated upstream of the completion device 12, thereturn point 6 downstream of the completion device 12.

[0030] The return track 9 and the one part of the supply track 3 betweenthe return point 6 and the transfer point 7 is implemented with asingle, circulating conveyor (last conveyor 20), by which at thetransfer point 7, completed products are either transferred to thestacking operation or are not transferred and conveyed onwards, and bywhich the supply stream is taken over at the return point 6, wherereturned products are fitted into gaps of the supply stream.

[0031] In addition to the completion device 12, three further,clock-cycled conveyors 21, 22 and 23 are provided for the supply track 3between the article delivering device 4 and the last conveyor 20. Thefirst conveyor 21 serves for conveyance from the delivering device 4 toa device 24 for producing storage units (e.g., rolls) of main products.

[0032] Such a first conveyor 21 and device 24 are usually provided asstandard equipment for the production of part products and supplementsbeing printed and arranged in storage formations off-line for beingsupplied later into the completion device 12 with the help of the partsupply systems 13.1 to 13.3. When producing main products on-line, thesupply stream is transferred from the first conveyor 21 to the secondconveyor 22 at the gap formation point 5, wherein main products to beremoved from the supply stream for forming gaps are conveyed onwards bythe first conveyor 21. From these removed main products, storageformations 30 are made for being e.g. supplied to be completed andpacked after the end of the web-fed printing press production or duringan interruption of it. The second conveyor 22 conveys the main productsto the completion device 12. The third conveyor takes over the completedmain products from the completion device 12 and conveys them to the lastconveyor 20, to which they are transferred at the return point 6.

[0033] FIGS. 4 to 6 illustrate in somewhat more detail than FIG. 3 crosssections through the installation according to FIG. 3 along theintersection lines designated with IV-IV, VV and VI-VI in FIG. 3.

[0034]FIG. 4 illustrates the first conveyor 21 designed as a gripperchain, the second conveyor 22 also designed as a gripper chain, thecompletion device 12 designed as a drum and the device 24 for producingstorage units (e.g., rolls) from main products removed from the supplystream.

[0035] The supply stream is transferred from the first conveyor 21 tothe second conveyor 22 at the gap formation point 5, wherein forproducing gaps main products are selectively not transferred butconveyed onwards by the first conveyor 21 to the device 24. The secondconveyor 22 conveys the supply stream onwards and transfers it to thecompletion device 12.

[0036]FIG. 5 illustrates the third conveyor 23 designed as a gripperchain, which takes over the supply stream (now comprising completed mainproducts) from the completion device 12 and transfers it to the lastconveyor 20 at the return point 6. The last conveyor 20 conveys theproducts from the return point 6 to the transfer point 7 and theretransfers them to the processing device 8. If there is no processingcapacity, products are not transferred at the transfer point 7 but arereturned back to the return point 6 by the last conveyor 20 and therethey are introduced into gaps of the supply stream.

[0037]FIG. 6 illustrates the first one of the part supply systemssupplying part products from the sheet feeder 14.1 to the completiondevice 12. In an as such known manner, this part supply system isdesigned as a gripper chain, which takes over the part products from thesheet feeder 14.1 and at the part supply point 16.1, transfers them tothe completion device 12. For making it possible to not supply the partproduct for a gap in the supply stream of the main products, thedistance (in conveying clock cycles) between the point where partproducts are taken over by the part supply system 13.1 and the partsupply point 16.1 is selected in such a manner, that it corresponds tothe distance between the gap formation point (5 in FIG. 3) and the partsupply point 16.1 and the gap in the supply stream of the main productsis produced simultaneously with the corresponding gap in the partproduct stream. The further downstream therefore, a part supply mergesinto the main product stream, the longer the part supply track betweenthe sheet feeder 14.1 and the completion device 12 is, as is indicatedin FIG. 3.

[0038] From FIGS. 3 to 6 it becomes clear, that an installation forcompleting and stacking/packaging main products delivered directly froma web-fed printing press with a main product supply according to themethod in accordance with the invention can be implemented using onlysimple conveying means operated in clocked cycles (e.g., withcirculating gripper chains operated at a substantially constant speed),and nonetheless only main products are removed, i.e. products which canbe reintroduced into the process in a simple manner, and nonetheless areduction in stacking/packaging capacity of a single stacking andpackaging device on producing peak packages can be absorbed without anyproblem.

1. Method for the sequential supply of articles (1) in a regularly clocked supply stream along a supply track (3) from an article delivering device (4) to an article processing device (8), the method comprising the steps of: depending on processing capacity, selectively transferring or not transferring supplied articles (1) to the article processing device (8) at a transfer point (7); conveying the not transferred articles (1) away from the transfer point (7) along a return track (9) to a return point (6) upstream of the transfer point (7); re-introducing the returned articles into the supply stream at the return point (6) and at a gap formation point (5) upstream of the return point (6) or at the return point (6), forming a gap (2) in the supply stream for every article to be reintroduced into the supply stream.
 2. Method in accordance with claim 1, wherein the articles (1) to be re-introduced and the gaps (2) are synchronized by matching a length in clock cycles of the return track (9) from the transfer point (7) to the return point (6), a length in clock cycles of a part of the supply track (3) from the gap formation point (5) to the return point (7) and a temporal difference in clock cycles between a non-transfer at the transfer point (8) and a gap formation at the gap formation point (5).
 3. Method according to claim 1, wherein the gaps (2) are formed by removing articles (1) from the supply stream.
 4. Method in accordance with claim 1, wherein the articles (1) are further processed along the supply track (3) between the gap formation point (5) and the return point (6) and wherein further processing is interrupted for each gap (2).
 5. Method according to claim 1, wherein the articles (1) are further processed along the supply track (3) between the return point (6) and the transfer point (7) and wherein further processing is interrupted for returned articles.
 6. Method in accordance with claim 4, wherein the articles (2) are main products delivered on-line by the article delivering device (4), wherein between the gap formation point (5) and the transfer point (6) said main products are completed in a completing device (12) by adding to each main product a plurality of part products and wherein in the article processing device (8), the completed main products are stacked and packaged in normal packages and peak packages.
 7. Method according to claim 6, wherein the part products are supplied to the completing device (12) in a plurality of part product streams and wherein gaps are produced in these part product streams, the gaps in the part product streams being synchronized with the gaps (2) in the supply stream of the main products.
 8. Device for supplying articles (1) in a clock cycled supply stream from an article delivering device (4) to an article processing device (8), said device comprising: conveying means for conveying the articles (1) in a clock cycled manner along a supply track (3) from the article delivering device (4) to a transfer point (7), transfer means located at the transfer point (7) for selectively transferring supplied articles (1) to the article processing device (8), conveying-away means for conveying away articles (1) not transferred at the transfer point (7), being equipped as return means for conveying the not transferred articles (1) along a return track (9) and for re-introducing the returned articles (1) into the supply stream at a return point (6) upstream of the transfer point (7) and gap forming means for forming gaps (2) in the supply stream at a gap formation point (5) upstream of the return point (6) or at the return point (6).
 9. Device in accordance with claim 8, wherein a length in clock cycles of the return track (9) from the transfer point (7) to the return point (6) is the same as a length of the one part of the supply track (3) from the gap formation point (5) to the return point (6).
 10. Device according to claim 8, wherein a length in clock cycles of the return track (9) differs from a length in clock cycles of the one part of the supply track (3) between the gap formation point (5) and the return point (6) by a time delay in clock cycles between a non-transfer at the transfer point (7) and formation of the corresponding gap.
 11. Device in accordance with claim 8, wherein a further processing device (10, 11) is situated along the supply track (3) between the gap formation point (5) and the return point (6) and/or between the return point (6) and the transfer point (7).
 12. Device according to claim 8, wherein for the one part of the supply track (3) from the return point (6) to the transfer point (7) and for the return track (9) a last conveyor (20) with a circulating conveying organ is provided.
 13. Device in accordance with claim 8, wherein the gap formation point (5) is designed as a controlled transfer from a first conveyor (21) to a second conveyor (22) such, that articles (1) remaining in the supply stream are transferred and articles (1) to be removed from the supply stream are conveyed onwards.
 14. Device according to claim 12, wherein the return point (6) is designed as a transfer point from a third conveyor (23) to the last conveyor (20).
 15. Device in accordance with claims 12, 13 and 14, wherein the first conveyor (21), the second conveyor (22), the third conveyor (24) and the last conveyor (20) are circulating gripper chains, on which grippers are arranged at regular distances between one another.
 16. Device according to claim 15, wherein the article delivering device (4) is a web-fed printing press and the article processing device (8) is a stacking/packaging device and wherein a completion device (12) is situated between the second conveyor (22) and the third conveyor (23).
 17. Device in accordance with claim 16, wherein for supplying part products to the completion device (12), a plurality of part supply systems (13.1 to 13.3) to part supply points (16.1 to 16.3) are provided, the length in clock cycles of which corresponds to the length of the supply track (3) from the gap formation point (5) to the corresponding part supply point (16.1 to 16.3). 